Radio Terminal and Base Station

1. A radio terminal for a mobile communication system, comprising: a receiver configured to receive a counting request, the counting request requesting transmission of a counting response from a plurality of radio terminals that are receiving a specific MBMS service or interested in the reception of the specific MBMS service, and a common resource setting from a network, the common resource setting indicating a common resource pool to be commonly used by the plurality of radio terminals for the transmission of the counting response; a controller configured to determine whether or not the radio terminal is receiving the specific MBMS service or interested in the reception thereof in response to receiving the counting request; and a transmitter configured to transmit the counting response to the network by using a radio resource included in the common resource pool in response to the determination that the radio terminal is receiving the specific MBMS service or interested in the reception thereof wherein the counting request includes a service identifier for each of a plurality of MBMS services, the common resource setting indicates a plurality of common resource pools that are each a common resource pool associated with a corresponding one of the plurality of MBMS services, the controller is configured to select one of the plurality of common resource pools that corresponds to the service identifier of the one of the plurality of MBMS services that the radio terminal is receiving or interested in the reception thereof, from among the plurality of common resource pools, and the transmitter is configured to transmit the counting response to the network by using a radio resource included in the selected common resource pool.

2. The radio terminal according to claim 1 , wherein the controller is configured to randomly select a subset of radio resources from the common resource pool, and the transmitter is configured to transmit the counting response to the network by using the selected subset of radio resources.

3. The radio terminal according to claim 1 , wherein the controller is further configured to acquire a random number generated by the radio terminal or a unique identifier of the radio terminal, and determine whether or not transmission of the counting response is permitted based on the random number or the unique identifier.

4. The radio terminal according to claim 3 , wherein the receiver is configured to further receive a predetermined value transmitted from the network, and the controller is configured to determine whether or not transmission of the counting response is permitted based on the random number or the unique identifier and based on the predetermined value.

5. The radio terminal according to claim 1 , wherein the controller is configured to acquire a random number generated by the radio terminal or a unique identifier of the radio terminal, and the controller is configured to determine a transmission timing of the counting response based on the random number or the unique identifier.

6. The radio terminal according to claim 5 , wherein the receiver is configured to further receive a predetermined value transmitted from the network, and the controller is configured to determine the transmission timing of the counting response based on the random number or the unique identifier and based on the predetermined value.

7. The radio terminal according to claim 1 , wherein the transmitter is configured to transmit, as the counting response, a common signal sequence commonly used by the plurality of radio terminals for the transmission of the counting response to the network.

8. The radio terminal according to claim 1 , wherein the controller is configured to acquire a random number generated by the radio terminal or a unique identifier of the radio terminal, and the transmitter is configured to transmit to the network a signal sequence, the signal sequence selected by using the random number or the unique identifier, as the counting response.

9. The radio terminal according to claim 1 , wherein the transmitter is configured to transmit the counting response to the network by using at least a subset of resources from the common resource pool when the radio terminal is in a state in which signaling is suppressed between the radio terminal and the network.

10. The radio terminal according to claim 1 , wherein the transmitter is configured to transmit, to the network, a request message for the radio terminal to restore from a state in which signaling is suppressed between the radio terminal and the network, and the request message includes information indicating that the radio terminal is receiving an MBMS service or interested in the reception thereof.

11. A base station for a mobile communication system, comprising: a transmitter configured to transmit a counting request, the counting request requesting transmission of a counting response from a plurality of radio terminals that are receiving a specific MBMS service or interested in the reception of the specific MBMS service, and a common resource setting, the common resource setting indicating a common resource pool to be commonly used by the plurality of radio terminals for the transmission of the counting response; and a receiver configured to receive the counting response transmitted by the plurality of radio terminals by using a radio resource included in the common resource pool, wherein the counting request includes a service identifier for each of a plurality of MBMS services, the common resource setting indicates a plurality of common resource pools that are each a common resource pool associated with a corresponding one of the plurality of MBMS services, and the receiver is configured to receive the counting response transmitted by the plurality of radio terminals by using a radio resource included in one of the plurality of common resource pools which is selected by the plurality of radio terminals from among the plurality of common resource pools, the one of the plurality of common resource pools corresponds to the service identifier of the one of the plurality of MBMS services that the plurality of radio terminals are receiving or interested in the reception thereof.